21698719 has 6 divisors (see below), whose sum is σ = 25241424. Its totient is φ = 18598860.

The previous prime is 21698713. The next prime is 21698731. The reversal of 21698719 is 91789612.

It is not a de Polignac number, because 21698719 - 2³ = 21698711 is a prime.

It is a super-2 number, since 2×21698719² = 941668812481922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21698711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 221367 + ... + 221464.

It is an arithmetic number, because the mean of its divisors is an integer number (4206904).

Almost surely, 2^21698719 is an apocalyptic number.

21698719 is a deficient number, since it is larger than the sum of its proper divisors (3542705).

21698719 is an equidigital number, since it uses as much as digits as its factorization.

21698719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442845 (or 442838 counting only the distinct ones).

The product of its digits is 54432, while the sum is 43.

The square root of 21698719 is about 4658.1883817639. The cubic root of 21698719 is about 278.9189566042.

The spelling of 21698719 in words is "twenty-one million, six hundred ninety-eight thousand, seven hundred nineteen".